Asteroid as the basis of a Space Station Posted on: Tue Dec 06, 2011 5:58 am

With NASA planning a manned mission to an asteroid in the near future, what do you think about returning trips to establish a permanent presence on an asteroid.

Before we sent anyone anywhere, asteroids would have to be surveyed from afar or by robotic probes to analyze terrain, geological composition, etc. The first missions to establish a presence there would be to leave on-surface habitat structures. This would include power plants (nuclear or solar), science experiments, living quarters. After an on-surface habitat has been made, robotic excavating machines would begin digging the permanent habitat tunnels beneath the surface. These machines would of course have to be able to dig, drill, blast, survey, and reinforce as they went along. Within these tunnels would be built the permanent habitat structures. The thick regolith above would protect from small impacts and from harmful radiation. An alternative to digging tunnels into the asteroid would be to build the habitat in trenches or craters, natural or dug out, then bury them with a protective layer of regolith.

This plan seems feasible with today's technology and resources. Possibly something that could be accomplished within the next 25-50 years.

I'm just throwing this concept out there for discussion. It's not a new concept.

Also, what sort of thrust would be needed to move an asteroid to a new orbit? Such as moving a NEO to a Lagrange point, or other Earth orbit? Or moving an asteroid into Mars orbit. Or pilot a Trojan asteroid to the outer planets?

I cant remember who came up with the idea but i quite liked the suggestion of getting an iron nickel asteroid of roughly cylindrical shape tunnelling lengthways down the centre of it filling the hole with an ice asteroid capping off with some of the iron/nickel tunnelled out then spin it up using some of the left overs as fuel. Then use a big space mirror(a parabolic mylar sheet) to melt it evenly. It would then inflate and you would have an instant O'Neil colony that just needs a few windows adding along with some plants etc to turn the melted dirty snowball into a viable biocylinder, quite simple really.

And icing on the cake would be if it was in an elliptical orbit between earth orbit and Mars orbit so it could be used as a really big space elevator with no need for cables. Then build recursively between the orbits of the asteroid belt and other planets just increasing size of mirrors used for melting and then reflecting light into the colonies on our way outwards.

_________________Someone has to tilt at windmills.So that we know what to do when the real giants come!!!!

You mean an "Cycler" not an elevator right? Thats a good idea, an asteroid solves a bunch of deep space problems.

SteveXE wrote:

Also, what sort of thrust would be needed to move an asteroid to a new orbit? Such as moving a NEO to a Lagrange point, or other Earth orbit? Or moving an asteroid into Mars orbit. Or pilot a Trojan asteroid to the outer planets?

its not that difficult if you aren't in a hurry. Its been hypothesized that you can just rig big solar sails to it and just that push will adjust the orbit over time.

However, I wouldn't expect to be able to park an orbit anywhere near Earth for the foreseeable future. Just the liability issue alone makes the idea DOA. But Mars or Venus wouldn't be a problem. Any kind of terraforming on either is going to require some cosmic billiards.

Step 0: survey potential asteroid sites to use looking at geological composition, orbit/location, size, etc...Step 1: first unmanned and manned missions delivering cargo and the first habitable surface modules as well as power sources (nuclear/solar)Step 2: digging underground tunnels and building underground habitat modulesStep 3: propulsion "tug" engines to maneuver the new "Asteroid Outpost" to a new orbit

This is something that we could do with today's technology, within the next 20-50 years easily (given the money to fund such a feat).

You mean an "Cycler" not an elevator right? Thats a good idea, an asteroid solves a bunch of deep space problems.

However, I wouldn't expect to be able to park an orbit anywhere near Earth for the foreseeable future. Just the liability issue alone makes the idea DOA. But Mars or Venus wouldn't be a problem. Any kind of terraforming on either is going to require some cosmic billiards.

Yes i could not remember the term cycler tho the effect would be a cable-less elevator going up and down the solar systems gravitational well if you think laterally along the planetary plane .

Doing a few near Venus would be good as you could make more efficient use of solar energy and it might be possible to use waste products from asteroid mining to help terraform Venus. And if you want some cosmic billiards now that pluto has been downgraded why not put a big linear accelerator on it and send a stream of lumps of ices of various kinds towards Mars to replenish its atmosphere and add some more water to it.

_________________Someone has to tilt at windmills.So that we know what to do when the real giants come!!!!

Also, what sort of thrust would be needed to move an asteroid to a new orbit? Such as moving a NEO to a Lagrange point, or other Earth orbit? Or moving an asteroid into Mars orbit. Or pilot a Trojan asteroid to the outer planets?

It depends on where in the orbit you make the delta V change. The earlier the better, a gentle nudge at Parigee makes for a massive change in orbit as it falls back toward the sun. This is for intermittant vectors, or "pushes", constant thrust tends to pile up over time, which might make for a better solution with the masses we're talking about. If you're mining En-route, you can just accellerate the unwanted minerals, like silicates for reaction mass.

If you're asking what Type of thruster would be best, it depends on the mission, and available tecnology. I'd vote for a thermal reactor with a thrust vent, since you need to break down the materials for refining, anyway. The metals can be captured magnetically, and volatiles boiled off into space.

Ion engines would be a poor choice, because most of them use uncommon noble propellants, like Xenon, which would have to be shipped the whole way there. I'd be more worried about power generation, because the main belt is about the edge of practical solar collection, not to mention filled with orbital velocity gravel, which probably wouldn't be good for the collection area.

Some radioisotope reactor, like we used on most of our deep space probes would probably work best. If we're talking Aten, Apollo, and hybrid orbit groups, they're not as high populations, but a lot closer, and some come within 5 times the distance to the moon on a fairly regular basis. (about 4 years for the ones on a Harmonic orbit with Jupiter.)

_________________"You can't have everything, where would you put it?" -Steven Wright.

Last edited by Psiberzerker on Wed Feb 29, 2012 7:23 pm, edited 1 time in total.

My current target for such an operation is 4179 Toutatis, because we don't need to change it's orbit. For a little background, this rocky mishapen wanderer is scheduled to swing by us this December at appelion, then swing back out toward Jupiter over the next couple years. Now, I doubt we could get a mission up, and running that fast, so I'll assume putting this together for 2016.

My proposal is, the first mission should be robotic, to autonymously core it out on the long coast, then come back with a large enough cavity to pressurize as a habitat volume. Then, around 2020, we can send a crew to continue mining, while it travels back right by the Main belt, disembark to set up the same equipment on another rock, and send that back towards our orbit.

Staying on Toutatis, the robotic miner can do it's thing, while the Crew makes the return trip. The nice thing about this is, we don't have to worry about thrust, except to catch up with it, then launch the gear to the new target. the rest of the time, you're just coasting, and mining for more volume, and minerals to sell when you get back to Earth. At that point, we could have a releif crew trained to rotate for the next mission.

Eventually, we could have rocks comming back every 4 years, for a sustainable industry to build habitats in, and outside of orbit. The latter asteroids could then be sent out on other favorable orbits to catch Mars, venus, and other targets of interest. At least in my science fiction, this turns out to be the lowest cost, and risk way to make interplanetary travel, and commerce routine, and profitable.

The safety thing is, inside a large metallic asteroid, the rock would protect you from Radiation, and Impactors (Barring a direct hit to the main docking hatch. I don't really like the Trench idea so much, because the surface gravity wouldn't be high enough to guarentee packing of the loose material enough to reliably stop impactors at interplanetary velocities.

_________________"You can't have everything, where would you put it?" -Steven Wright.

Yeah its a good target. Besides its near approach to Earth, its resonance with Jupiter could make it a good way-point or even piggyback for a Earth-Jovian "trade route".

However, it has a couple of problems.

One, it has a 2 axis tumbling rotation. While its relatively slow, giving it a "day" of 2-5 Earth days, this will make landing on it tricky and make solar energy collection less effective.

Also it is a "rubble pile" asteroid, not a cohesive monolithic body.

That means, unless you can locate large boulder blocks to excavate into, you aren't like to be able to pressurize tunnels. Most of it is probably like regolith. Loose dust and small rocks. Will probably be a challenge to learn to work in that environment.

Yeah, it's tumbling, but as you pointed out, slowly. We're not sure about it's solidity, but there are some theories that it's actuslly a contact-binary, or 2 masses stuck together by gravity. To me, this suggests at least one is a solid mass underneath (It would have to be the larger one, you can't have a pile on a smaller solid mass) it would have likely settled into a somewhat more spherical shae by now.

I think the complications these present are dwarfed by the bare budget delta vee neccissary to find out. Nothing else comes this close, so regularly, so even if it can't be hollowed out as a Nomad Station (My term), a rubble pile would be better suited for mining as you don't need as much equipment to pick up rocks, and dust to ship back.

Another point towards at least going to check it out in a few years is it's a potential impactor, so any presence on it would put us that much closer to being able to alter it's trajectory into something other than a collision (Or at least detouring at the desolate moon.) Regardless, I think it's regular proximity makes it an ideal candidate for an exploratory mission, it gets well within range of a crewed scouting with technology we could develop in about 5 years. If not nine, or 13, and a half. Even if we miss a window, whe know they'll be back.

_________________"You can't have everything, where would you put it?" -Steven Wright.

Not to dismiss the possibility of it, or them being a "Rubble Pile" mass, I thought I'd address it seperately. This is not damning, but does modify the proposal quite a bit. 1st of all, such a mass can't be rotated for Gravity (Simulation, actually outward Acceleration) because the surface force downward is what holds it together in the first place, so if you spin it outward, everything on the surface ceases to be there, and you've transformed 1 mass into a shotgun pattern of potential meteorites. This is even worse if there is a solid mass, or masses under all that, because they could be large enough to hit the surface of the Erath before burning up, or explode low enough for a Tunguska like blast.

Let's try to avoid that, so should it turn out to be a collection, I'll just skuttle the idea of spinning it up. First priority would still be to regularize the rotation to something you can land on easilly. Because it's closest pass to Earth is at apogee, that's also it's highest velocity (so it's orbit can take it all the way out past the main belt) The last thing we want is to make it into a potential impactor.

The trick to landing on it would be timing, and good piloting. For this, I would suggest a crewed mission simply for reaction time, because the (Minimum) 7 second lag of transmission would make attempts remotely impossible. That doesn't mean the crew has to land initially, though. I'd follow it at a safe distance, and remotely pilot probes to hopefully land safely. If not, we're out some hardware, try again in a few more years.

The broken composition would also limit our options to effect changes to rotation. If it were completely solid, we could concievably use impacts to transfer momentum, but this would raise too much risk of knocking peices off, and thereby risk the crew, if not Earth. I'd suggest landing thrusters, which would be neccessary to get there any way, or possibly vaporize, and fuse the surface with heat.

We could do this with a condenser, either a mirror, or lens to focus solar radiation on the surface. No blasts, mind you, but the light volatile elements would come off as gas/plasma, which wouldn't have the risk of becoming schrapnel, and the heavier elements pool as a fluid to cool, and slidify withoutt flying off. the problem here is, that would take a lot of energy, which means a large condensor, which means a lot of fuel to get it there.

I've been thinking of similar techniques to fuse regolith into tunnels for habitiation. Any ideas? I know you guys are pretty good at brainstorming, and I wouldn't mind a little help. This concept has all the earmarks of a story I've been wanting to write for a long time, and I would certainly kick down at least credit for any help with the worldbuilding. (If you'll pardon the expression?)

_________________"You can't have everything, where would you put it?" -Steven Wright.

Another idea I've been kicking around for normalizing rotation would involve a surface rover, and re-usable thruster to land, and take off again with material as part of the mining operation. Again remote-robotic, it's probably far too risky for the crews, but by telemetry from a nearby scout vehicle.

Every time you land, and take off, you're adding and subtracting mass. To be profitable, we'd need to make several such trips. By picking the sites (with the rover to move between them), the change in mass, and thrust would affect the complex rotation. We could slowly, and carefully do it in such a way as to subtract from the erratic spins, and eventually counter them completely. (Hopefully in about 4 years.)

Meanwhile, we'd be collecting, studying, and refining the regolith for sale apon return to our neighborhood. With any luck, there may be resources we could use in situ, such as volatiles, and reaction mass. A lot of the minerals detected specroscopically back in the nineties are silicates, which we have plenty of at home, so these could be refined, and hydrolyzed (From the solar wind) into Silane. All we'd need then would be a workable silane thruster to run off it. Silane may be oxydized by CO2, which isn't exatly rare, what with being a byproduct of our biology. At any rate, this would prevent us wasting our Oxygen supplies until after we've already used it.

The advantage of this idea is it would control all mass leaving the surface, instead of liberating it ass potential schrapnel. The main disadvantage would be the technologies we'd have to develop, but they're all near future, as far as I can see, and we'd be facing that prospect (Pardon the expression) anyway.

_________________"You can't have everything, where would you put it?" -Steven Wright.

Toutatis is only a few kilometres a side, on the same order of magnitude as the largest trawling nets used for fishing. If it's a rubble pile, why not wrap a big net around it to keep the bits together?

_________________Say, can you feel the thunder in the air? Just like the moment ’fore it hits – then it’s everywhereWhat is this spell we’re under, do you care? The might to rise above it is now within your sphereMachinae Supremacy – Sid Icarus

It would have to be more a fine mesh to contain the fines, like nylon stockings. And it still masses megatons, if that got moving, it would easily overwhelm the tensile strength of the material. Same goes for sintering the surface together.

Still, one of the projected hazards of dealing with these kind of asteroids is that disturbing them could kick up a dust cloud that takes forever to settle. It will become a haze of dust pollution getting in the way and into machinery. Putting it in a "sock" might be a way of mitigating that.